Retractable device

ABSTRACT

A self-locking retractable surgical knife including a sheath member having front and rear ends, and a retractable member including a support member and a blade supported by the support member. The support member has a front end, a rear end and an elongated interior space. The retractable member is partially disposed in the sheath member and telescopically received in the sheath member for movement between a guarded position wherein the blade is guarded in the sheath member, and an exposed position wherein the blade extends out of the sheath member. The self-locking retractable further includes a biasing member disposed in the interior space of the support member and a latch member disposed in the interior space of the support member.

FIELD

The present invention relates generally to retractable devices that canbe positioned in a guarded position and an exposed position.

BACKGROUND

Scalpels are a class of knives used in the surgical environment for avariety of uses including incising, stabbing and shaving human andanimal skin and tissues. Conventional scalpels used for this purposehave a stationary blade. The blade is always exposed thereby creating ahazard of inadvertent puncture to an operating room team member or toany other person who may come in contact with a scalpel, especially whomay come in contact with a used scalpel. For example, in some emergencysituations, a surgeon must work quickly and hand instruments back andforth to assistants. It is dangerous sometimes because the sharpscalpels can accidentally cut or jab the personnel's hands during theoperation. Certain fatal infections can be transferred to individualsthrough small cuts. The primary hazard of skin puncture is the possibletransmission of an infectious agent, such as H.I.V., hepatitis B. andhepatitis C. The sequelae of scalpel injuries are emotionally traumaticand potentially expensive for the institution involved. In the operatingroom, scalpels cause 18% of injuries. Reusable scalpels, which requireblade removal in order to reuse the handle, cause more than twice asmany injuries as disposable scalpel.

To reduce injuries from scalpel blades, a variety of strategies areneeded that address the different mechanisms of scalpel injuries. Theuse of a retractable scalpel in the operating room will eliminate thesimultaneous handling of sharps by two people. Thus, scalpels withretractable blades that can be placed in a protective position duringpassing of the device and after use have the potential to prevent alarge proportion of scalpel injuries to as much as 65%.

SUMMARY

Some embodiments of a retractable device can be configured to allow thedevice to be positioned in an exposed position and a guarded position.For example, the retractable device can include a sheath member havingan interior space; a retractable member disposed in the interior spaceof the sheath member and moveable longitudinally between an exposedposition and a guarded position relative to the sheath member; a biasingmember disposed longitudinally within the retractable member; and alatch member that locks the retractable member relative to the sheathmember in the guarded position. In such circumstances, the latch membercan include a release button extending through both the retractable andthe sheath members. The retractable member is movable from the exposedposition to the guarded position in response to the release button beingpushed by a user.

Some embodiments include a self-locking retractable surgical knifeincluding a sheath member having front and rear ends; a retractablemember including a support member and a blade supported by the supportmember, wherein the support member has a front end, a rear end and anelongated interior space; the retractable member being partiallydisposed in the sheath member and telescopically received in the sheathmember for movement between a guarded position wherein the blade isguarded in the sheath member, and an exposed position wherein the bladeextends out of the sheath member; top and bottom elongated andlongitudinally extended slots formed on the support member, wherein thetop slot is defined in a top wall of the support member and the bottomslot is defined in a bottom wall of the support member, a biasing memberdisposed in the interior space of the support member; a latch memberdisposed in the interior space of the support member, the latch memberhaving a release button projecting through the top slot of the supportmember and an opening defined in a top wall of the sheath member in thisorder, the latch member having a bottom section projecting through thebottom slot of the support member and abut the inner surface of thebottom wall of the sheath member; and a self-locking mechanismconfigured to translate an axial movement of the retractable member whenthe retractable member is moving from the exposed position to theguarded position to rotation, thereby preventing the retractable memberfrom moving forward relative to the sheath member and self-locking theretractable member in the guarded position.

Other embodiments include a retractable tool holder including a sheathmember having front and rear ends; a retractable member including asupport member and a tool head retention element supported by thesupport member, wherein the support member having an elongated interiorspace; the retractable member being partially disposed in the sheathmember, and telescopically received in the sheath member for movementbetween a guarded position wherein the tool head retention element isretracted into the sheath member, and an exposed position wherein thetool head retention element extends out of the sheath member; top andbottom elongated and longitudinally extended slots formed on the supportmember wherein the top slot is disposed along a top side of the supportmember and the bottom slot is disposed along a bottom side of thesupport member; a top opening defined in a top side of the sheathmember; a biasing member disposed in the interior space of the supportmember; a latch member for latching the retractable member in theexposed position, the latch member having a release button beingreceivable in the top opening of the sheath member and the top slot ofthe support member, thereby locking the sheath member and the supportmember against further relative movement; and a self-locking mechanismconfigured to translate an axial movement of the retractable member whenthe retractable member is moving from the exposed position to theguarded position to rotation, thereby preventing the retractable memberfrom moving forward relative to the sheath member and self-locking theretractable member in the guarded position.

Further embodiments include a method of assembling a retractable deviceincluding inserting a rear end of a retractable member into an openingat a front end of a sheath member, with an elongate top slot of theretractable member aligned with an elongate top slot of the sheathmember; introducing a latch member into an interior space of theretractable member between a sliding pin and a rear end of the elongatetop slot of the sheath member from the overlapped elongate top slots ofthe retractable member and the sheath member; and inserting a biasingmember into the interior space of the retractable member through abiasing member introduction slot.

This Summary is an overview of some of the teachings of the presentapplication and not intended to be an exclusive or exhaustivedescription of the claimed invention. Further details about the presentsubject matter are found in the detailed description and appendedclaims. Other aspects of the subject matter will be apparent to personsskilled in the art upon reading and understanding the following detaileddescription and viewing the drawings that form a part thereof, each ofwhich are not to be taken in a limiting sense. The scope of the claimedinvention is defined by the appended claims and their equivalents.

DESCRIPTION OF THE DRAWINGS

The drawings, which are not necessarily drawn to scale, illustrategenerally, by way of example, but not by way of limitation, variousembodiments discussed in this application.

FIG. 1A is a perspective view of an embodiment of a retractable devicein an exposed position.

FIG. 1B is a perspective view of the retractable device illustrated inFIG. 1A in a guarded position.

FIG. 2 is an exploded view of a further embodiment of the retractabledevice.

FIG. 3A is a cross sectional view of the retractable device illustratedin FIG. 2, when the device is in an exposed position.

FIG. 3B is a further cross sectional view of the retractable deviceillustrated in FIG. 2, when the device is in a guarded position.

FIG. 4A is a perspective view of a latch member of the retractabledevice of FIG. 2, with the latch member positioned in an extendedposition.

FIG. 4B is a side view of the latch member illustrated in FIG. 4A.

FIG. 4C is a side view of the latch member of FIG. 4A, with the latchmember positioned in a fully-compressed position.

FIGS. 5A-C are top, side and bottom views of the retractable member ofthe retractable device illustrated in FIG. 2.

FIGS. 6A-B are perspective views of a support member of the retractablemember illustrated in FIGS. 5A-C.

FIG. 6C is a cross sectional view of a locking bridge of the supportmember illustrated in FIG. 6A along line 6 c-6 c.

FIG. 6D is a rear end view of the support member illustrated in FIG. 6A.

FIG. 7A is a cross sectional view of the support member illustrated inFIG. 6A.

FIG. 7B is a cross sectional view of the support member illustrated inFIG. 7A with the latch member assembled therein, when the retractabledevice is in an exposed position.

FIG. 7C is a cross sectional view of the support member illustrated inFIG. 7A with the latch member assembled therein, when the retractabledevice is in a guarded position.

FIG. 7D is a cross sectional view showing a beveled or tapered edge ofthe locking bridge of the support member illustrated in FIG. 7Acontacting a detent element of the latch member.

FIG. 8A is a perspective view of a sheath member of the retractabledevice.

FIG. 8B is a cross sectional view of the sheath member of FIG. 8Acooperating with the retractable member and the latch member, when theretractable device is in the exposed position.

FIG. 8C is a cross sectional view of the sheath member of FIG. 8Acooperating with the retractable member and the latch member, when theretractable device is in the guarded position.

FIG. 8D is a side view of a rear end portion of the sheath membershowing a compression member.

FIG. 9A is a sectional view of a compression member of the sheath memberof FIGS. 8A-D.

FIGS. 9B-D are sectional views of alternative embodiments of thecompression member.

FIGS. 10A-B are cross sectional views showing an assembling process ofthe retractable device.

FIG. 11 is a perspective view showing a further embodiment of theretractable member with a biasing member disposed therein.

FIGS. 12A-B are perspective views of a still embodiment of a sheathmember.

FIG. 13A is a perspective view of a yet further embodiment of aretractable device showing a locking mechanism.

FIGS. 13B-E are perspective views of a support member of the retractabledevice of FIG. 13A, with a latch member disposed in an interior space ofthe support member.

FIG. 14A is a perspective view of an even further embodiment of aretractable device in an unlocked position.

FIG. 14B is a perspective view of the retractable device of FIG. 14A ina locked position.

FIGS. 14C-F are perspective views of a support member of the retractabledevice of FIG. 14A, with a latch member disposed in an interior space ofthe support member.

FIG. 15 includes a perspective view of a sheath member of a furtherembodiment of the retractable device with a self-locking mechanism and aduplicate of the perspective view of FIG. 8A for comparison.

FIG. 16 A is a cross-section view of the sheath member of FIG. 15.

FIG. 16B is a front end view of the sheath member of FIG. 15.

FIG. 17A is a top perspective top view of a retractable member of thefurther embodiment of the retractable device with an automatic lockingmechanism.

FIG. 17B is a bottom perspective top view of the retractable member ofFIG. 17A.

FIG. 18 is a cross-section view of the sheath member, the retractablemember and the latch member when the retractable device is beingassembled.

FIG. 19A is a sectional view of the retractable device of FIG. 18, witha blade being in an exposed position.

FIG. 19B is a sectional view of the retractable device of FIG. 18, withthe blade being partially retraced.

FIG. 19C is a sectional view of the retractable device of FIG. 18, withthe blade being in a guarded position.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings which form a part thereof, and in which is shownby way of illustration specific embodiments in which the inventiveconcepts may be practiced. These embodiments are described in sufficientdetail to enable those skilled in the art to practice the invention, andit is to be understood that the embodiments may be combined or usedseparately, or that other embodiments may be utilized and thatstructural and procedural changes may be made without departing from thespirit and scope of the inventive concepts. The following detaileddescription provides examples, and the scope of the present invention isdefined by the claims to be added and their equivalents.

The terms “above,” “on,” “under,” “top,” “bottom,” “up,” “down,”“front,” “rear,” “horizontal,” and “vertical” and the like used hereinare in reference to the retractable device and the relative positions ofits constituent parts, in use when oriented as in the figures.

As used herein, the term “integrally formed” refers to the componentbeing one-piece and/or being formed as a one-piece component, such as astructure having components that are fixedly connected or mountedtogether in any suitable manner. The term “polyvinylidene fluoridepolymer” and acronym “PVDF” refer to the homopolymer, copolymer andterpolymer. It also refers to similar material having an equivalentfunction. The term “detectable condition” refers to the indication,which may be detected, that tells whether a retractable device is lockedin a guarded position. The term “indicia” refer to any mark intended toconvey information to the viewer. For example, indicia may includeletters, numerals, symbols, characters, designs, pictures, decorations,shapes, geometries, textures, colors or combinations thereof, amongother means of relaying information to the viewer.

A retractable device 10 is illustrated as, by way of illustration butnot limitation, a retractable surgical knife as shown in FIGS. 1A-B. Insome embodiments, the retractable device 10 may include a sheath member12, a retractable member 14 received telescopically within the sheathmember 12, a latch member 16 and a biasing member 18. In suchcircumstances, the retractable member 14 can be positioned in an exposedposition (as shown in FIG. 1A) and a guarded position (as shown in FIG.1B) relative to the sheath member 12. In some embodiments, when theretractable device 10 is positioned in the exposed position, the lengthof the retractable device 10 is similar to that of a regular scalpel.This allows the retractable device 10 to have a simple structure and tobe cost-effective to assemble, while maintaining a high retractionspeed. Moreover, it is intuitive for a user to push a rear end of theretractable member 114 to expose the tool head and push a button on thelatch member 16 to retract the retractable member 14. The retractablemember 14 can include a tool head 50 and a support member 52, with thetool head 50 being coupled to the support member 52.

It is to be understood that although in the embodiments depicted in thedrawings of this disclosure, the sheath member and the retractablemember are both depicted as having a circular cross section when theyare cut by a plane perpendicular to a longitudinal axis of the sheathmember, the cross section of the sheath member and the cross section ofthe retractable member can have other shapes, such as oval shapes,elliptical shapes, hexagonal shapes, other polygonal shapes, or othershapes. In some embodiments, such as the embodiment shown in FIGS. 1A-B,the shape of the cross section of the retractable member generallytracks the shape of the cross section of the sheath member.

In some embodiments, the length of the retractable device 10 in theexposed position can be similar to that of a non-retractable device. Forexample, a length of a retractable surgical knife in the exposedposition can be similar to that of a non-retractable scalpel.

In some embodiments, most parts of the retractable device 10 can be atleast partially made of non-metal materials, such as plastic materials,to allow it to be light so that easier to be manipulated. The lower costof the materials of the retractable device 10 allows the retractabledevice 10 to be relatively inexpensive to make, and as a result, allowthe device 10 to be disposable. This will further reduce the cost andsafety issues for sterilizing the retractable device 10 and changing thetool head 50. Examples of plastic materials may have good mechanical andchemical resistance properties that are retained to high temperatures,such as semicrystalline thermoplastic materials like Polyether etherketone (PEEK) and polyvinylidene fluoride polymer (PVDF). These plasticmaterials can be used to make parts of the retractable device, such asthe sheath member 12, the retractable member 14 and the latch member 16.

In some embodiments, the biasing member 18 can be made of metal ormetals. However, in some embodiments, the biasing member 18 can also bemade of non-metal materials, such as plastic materials, silicon or canbe coated with a microfilm (e.g. TEFLON™) or other types ofpolypropylene materials so that the biasing member 18 is heat/steamresistant and chemical resistant. The tool head 50 can be made ofnon-metal materials, such as plastic material, and metal or othermaterials. Accordingly, almost all parts of the retractable device 10can be injection molded. This can help lower the cost for manufacturingthe retractable device 10 more effectively. It is to be understood thatin some embodiments, most parts of the retractable device 10 can be madeof other materials, such as metal or metals.

In some embodiments, a retractable device 10 can consist essentially ofonly five integrally formed components: a sheath member 12, aretractable member 14, a latch member 16 and a biasing member 18. Insuch circumstances, loss of components such as pins, screws, fasteners,links, springs or the like during use or storage of the retractabledevice can be prevented. This is useful when the retractable device 10is a retractable surgical knife. In such circumstances because it willhelp reduce safety issues if loss of components such as pins, screws,fasteners, links, springs or the like in the operative field can beprevented. In addition, fewer components allow easy assembly of theretractable device 10 and as a result allow the cost for manufacturingthe device 10 to be lowered more effectively.

FIGS. 2 and 3A-B show a particular embodiment of the retractable device10. As depicted in FIGS. 2 and 3A-B, a retractable device 110 consistsessentially of only four integrally formed components sheath member 112,retractable member 114, latch member 116 and a biasing member 118. Insuch circumstances, loss of components such as pins, screws, fasteners,links, springs or the like during use or storage of the retractabledevice can be prevented. This is useful when the retractable device 110is a retractable surgical knife. In such circumstances because it willhelp reduce safety issues if loss of components such as pins, screws,fasteners, links, springs or the like in the operative field can beprevented.

However, it is to be understood that in other embodiments theretractable device 110 can include more than four integrally formedcomponents. The retractable device 110 has an axial direction X and aradial direction Y. The retractable member 114 can be positioned in anexposed position (as shown in FIG. 3A) and a guarded position (as shownin FIG. 3B) relative to the sheath member 112. Compared to the positionin FIG. 3A, the retractable member 114 has retracted a retractiondistance d_(R) in FIG. 3B.

In some embodiments, the length of the retractable device 110 can beabout 5.56 inches. The length of the sheath member 112 and the length ofthe retractable member 114 can be about 71.93 mm, respectively. In otherembodiments, the length of the sheath member 112 is longer than thelength of the retractable member 114 whereby in one embodiment,retractable member 114 is entirely received in the sheath member 112when the retractable member 114 is positioned in the exposed position.In some embodiments, the length of the retractable device 110 in theexposed position can be similar to that of a non-retractable device. Forexample, a length of a retractable surgical knife in the exposedposition can be similar to that of a non-retractable scalpel.

Referring to FIGS. 4A-C, in some embodiments, the retractable deviceincludes the latch member 116 to releasably maintain the retractablemember 114 when the retractable member is positioned in the guardedposition. In such circumstances, the latch member 116 can have aU-shaped latch body 117. As shown in FIGS. 4B-C, the latch member 116can be positioned in an expanded position (referring to FIG. 4B) and afully-compressed position (referring to FIG. 4C) with at least a portionof the lower limb 122 being in contact with the upper limb 120. Thelatch body 117 can be made of suitable material having sufficientresilience and ultimate strength so that it is not easily broken underpressure. For example, the latch body 117 can be made of non-metalmaterials, such as plastic materials. Examples of plastic materials mayhave good heat resistance and solvent resistance, high dielectricstrength, natural flame resistance, such as ULTEM™ plastics availablefrom Saudi Basic Industries Corporation of Riyadh, Saudi Arabia.

In some embodiments, the latch body 117 can have a resilient upper limb120, a resilient lower limb 122 and a connecting section 124. For theconvenience of description, the left end of the latch body 117 where theconnecting section is located is described as a front side and the rightend of the latch body 117 is described as a rear side, as they areoriented in an assembled retractable device 110, as shown in FIGS. 4A-C.The connecting section 124 connects the front ends of the upper limb 120and the lower limb 122, respectively. In some embodiments, the lowerlimb 122 has an arm segment extending rearward defining an axialdirection x of the latch member 116 and the connecting section 124extending downwardly defining a radial direction y of the latch member116. When assembled, the axial direction x of the latch member 116 isgenerally oriented in the same direction as the axial direction X of theretractable device 110, and the radial direction y of the latch member116 is generally oriented in the same direction as the radial directionY of the retractable device 110.

Referring to FIG. 4A, in some embodiments, the latch member 116 has auniform width W. However, it is to be understood that the widths of theupper limb 120, lower limb 122, connecting section 124 and their variouscomponents can vary as long as the upper limb 120, lower limb 122,connecting section 124 and their components can cooperate properly withopenings or slots defined in the sheath member 112 and retractablemember 114 during the process of assembly or use.

As depicted in FIGS. 4A-C, in some embodiments, the upper limb 120includes an elongated arm segment 121 extending axially and slightlyupwardly relative to the axial direction x. The arm segment 121 has alength L_(UA) and a thickness T_(UA). The arm segment 121 has an uppersurface and a lower surface generally parallel to each other. An angle αis defined between the arm segment 121 and the axial direction x.

In some embodiments, the upper limb 120 can further include a releasebutton 126 configured to release a latch between the sheath member 112and the retractable member 114, thereby allowing the retractable member114 to retract from the exposed position. In such circumstances, therelease button 126 can protrude beyond the outer surface of the sheathmember 112. As a result, the release button 126 can help prevent theretractable device 110 from rolling more than 180 degrees on a flat ofslightly inclined surface.

The release button 126 can extend upwardly from an upper surface of thearm segment 121, with a front surface 125 of the release button 126extending upwardly in a generally radial direction y from the uppersurface of the arm segment 121. The front surface 125 has a height H. Anangle β is formed between the front surface 125 of the release button126 and the upper surface of the arm segment 121.

In some embodiments, the release button 126 may include a top surface129 having a length L_(B) and an inclined button ramp 127 configured toallow a low friction contact to be formed when the release button 126 ispressed downwardly to release the latch between the sheath member 112and retractable member 114.

The button ramp 127 can extend from a rear edge of an upper surface ofthe release button 126 downwardly and rearward. A positioning step 128extends from a lower edge of the button ramp 127 rearward in generallythe axial direction x of the latch member 116. In such circumstances,the positioning step 128 can help limit the release button 126 fromtraveling upwardly beyond a top wall of the retractable member 114. As aresult, the positioning step 128 defines a radial position of the latchmember 116 relative to the sheath member 112, and in turn defines aradial position of the latch member 116 relative to the retractablemember 114. In such circumstances, the positioning step 128 can helplocate a detent ramp 134 of the latch member 116 for a successfullocking action.

As shown in FIGS. 4A-C, an angle γ can be formed between the button ramp127 and the positioning step 128. In such circumstances, the upper limb120 can include a detent element 132 located at a rear portion of theupper limb 120. The detent element 132 is configured to allow the upperlimb 120 to be deflected downwardly, thereby allowing a portion of theretractable member 114 to pass through the detent element 132 and bereceived in a locking slot 130 formed between the detent element 132 andthe positioning step 128, when the retractable device 110 is assembled.As a result, the retractable member 114 can be latched to the sheathmember 112, allowing the retractable member 114 to be maintained in theexposed position. The locking slot 130 can have a length L_(S) definedbetween the positioning step 128 and a front surface 131 (referring toFIG. 4B) of the detent element 132.

In some embodiments, the detent element 132 can extend upwardly from thelocking slot 130 to a detent apex 133 and then angles rearward anddownwardly toward a rear end 135 of the upper limb 120. As shown inFIGS. 4A-C, the detent apex 133 is located at a distance d_(AS) from alower surface of the positioning step 128. The detent ramp 134 can bedefined between the detent apex 133 and the rear end 135. The detentramp 134 can be configured to deflect the upper limb 120 rapidly andsmoothly and thereby allows the retractable member 114 to be latchedwith the sheath member 112 effectively.

As shown in FIGS. 4A-C, an angle γ can be formed between the detent ramp134 and the axial direction x. In some embodiments, the upper limb 120can include a latch positioning apex 136 located on a lower surface ofthe upper limb 120. The latch positioning apex 136 can be locatedgenerally below the positioning step 128. However, it is to beunderstood that the latch positioning apex 136 can be located at otherlocations on the lower surface of the upper limb 120. The latchpositioning apex 136 can be located at a distance d_(BA) from the topsurface 129 of the release button 126.

Still referring to FIGS. 4A-C, a lower limb nesting ramp 137 can beformed at a lower surface of the upper limb 120 on a rear side of thelatch positioning apex 136 to allow a front portion of the lower limb122 to nest thereupon, when the lower limb 122 is compressed to theupper limb 120. A lower edge of the button ramp 127 is located at adistance d_(SR) from the lower limb nesting ramp 137. An arm segment 138of the lower limb 122 has a length L_(LA) and a thickness T_(LA) and theconnecting section 124 has a length L_(C) and a thickness T_(C).

In some embodiments, the distance d_(BA) is configured to be no greaterthan an inner diameter of the sheath member 112. However, it is to beunderstood, in other embodiments, a lowest end 196 of the lower limb 122is positioned vertically further away from the top surface 129 of therelease button 126 than the latch positioning apex 136, when the latchis in a fully-compressed position. This configuration allows the latchmember 116 to slide easily to its position during an assembling process.

In some embodiments, the thickness T_(UA) of the upper limb 120 and thethickness T_(LA) of the lower limb 122 can be generally equal to eachother, and the thickness T_(C) of the connecting section 124 is greaterthan the thickness T_(UA) of the upper limb 120 or the thickness T_(LA)of lower limb 122, thereby allowing an adequate elastic force to beproduced for actuate the latch member 116. However, it is to beunderstood that in other embodiments, the thickness T_(UA) of the upperlimb 120 and the thickness T_(LA) of the lower limb 122 can be differentfrom each other.

In some embodiments, the lower limb 122 can have the arm segment 138 anda balancing element 140. The balancing element 140 has an upper portion142 and a lower portion 144. The upper portion 142 has a length L_(BU)and the lower portion 144 has a length L_(BL).

As shown in FIGS. 4A-C, an angle θ is formed between the arm segment 138and the upper portion 142, and an angle φ is formed between the upperportion 142 and the lower portion 144. The lower limb 122 is configuredto allow at least a portion of the balancing element 140 to extendoutside the retractable member 114 when installed in the retractablemember 114 to balance the movement of the retractable member 114relative to the sheath member 112.

In addition, the lower limb 122 is configured to allow an upper surface123 of the lower portion 144 of the balancing element 140 to nest uponthe lower limb nesting ramp 137, which is formed on the lower surface ofthe upper limb 120. In some embodiments, when the latch member 116 ispositioned in the fully-compressed position, the entire upper surface123 of the lower portion 144 of the balancing element 140 rests on thelower limb nesting ramp 137. In some embodiments, when the latch member116 is positioned in the fully-compressed position, at least a portionof the upper surface 123 of the lower portion 144 of the balancingelement 140 rests on the lower limb nesting ramp 137. In someembodiments, when the latch member 116 is positioned in thefully-compressed position, a convex point 1221 formed between the upperportion 142 and the lower portion 144 of the balancing element 140 nestsat a concave point 1201 formed between the lower limb nesting ramp 137and the arm segment 121 of the upper limb 120.

In the embodiment depicted in FIGS. 4A-C, rigid transitions are formedbetween the arm segment 138 and the upper portion 142, and between theupper portion 142 and the lower portion 144. In other embodiments, asmooth transition, such as a smooth curved transition, can be formedbetween these portions.

In some particular embodiments, the length L_(UA) of the arm segment 121of the upper limb 120 can be about 0.40 inches, the angle α definedbetween the arm segment 121 and the axial direction x can be about 5°,the height H of the front surface 125 of the release button 126 can beabout 0.16 inches. In such circumstances, the angle β, which is formedbetween the front surface 125 of the release button 126 and the uppersurface of the arm segment 121, can be about 95°, thereby aiding in anunimpeded retraction of the retractable device 110. Specifically, whenthe retractable device 110 is in use, the angle β, when being slightlygreater than 90°, allows a front end 197 of the upper limb 120 to bepositioned slightly away from an inner surface of the sheath member 112to form a gap 199, thereby allowing a top wall portion 198 of theretractable member 114 to pass through the gap 199 between the upperlimb 120 and the inner surface of the sheath member 112 (referring toFIG. 3A). As a result, the top wall portion 198 of the retractablemember 114 can travel continually to its resting position against thefront surface 125 of the release button 126.

In these particular embodiments, the length L_(B) of the top surface 129of the release button 126 can be about 0.15 inches, the angle γ formedbetween the button ramp 127 and the positioning step 128 can be about102°, the length L_(S) of the locking slot 130 can be about 0.08 inches,the distance d_(AS) between the detent apex 133 and the lower surface ofthe positioning step 128, can be about 0.07 inches, the angle δ formedbetween the detent ramp 134 and the axial direction x can be about 140°,the distance d_(BA) between the latch positioning apex 136 and the topsurface 129 of the release button 126 can be about 0.30 inches, thedistance d_(SR) between the lower edge of the button ramp 127 and thelower limb nesting ramp 137 can be about 0.09 inches, the length L_(LA)of the arm segment 138 of the lower limb 122 can be about 0.24 inches,the length L_(C) of the connecting section 124 can be about 0.19 inches,the thickness T_(LA) of the arm segment 138 of the lower limb 122 can beabout 0.05 inches, the length L_(BU) of the upper portion 142 of thebalancing element 140 can be about 0.15 inches, the length L_(BL) of thelower portion of the balancing element 140 can be about 0.10 inches, theangle θ formed between the arm segment 138 and the upper portion 142 canbe about 157°, and the angle φ formed between the upper portion 142 andthe lower portion 144 can be about 148°.

Referring to FIGS. 5A-C, in some embodiments, the retractable member 114has a support member 152 and a tool head 150 mounted on a front end 158of the support member 152. In such circumstance, the tool head 150 canbe configured to be retracted entirely into the sheath member 112, andthereby shielded entirely in the sheath member 112.

However, it is to be understood that in other embodiments, the tool head150 does not have to be retracted entirely into the sheath member 112 solong as the tool head 150 is safeguarded from injuring the user.

In some embodiments, the tool head 150 is a blade having a cutting edge153 and a front point 155. The front point 155 can be rounded, astypical for standard #10 blades. In addition, the front point 155 can bepointed, as found in standard #11 blades, or like a hook, as found instandard #12 blades. The blades can also be small tip blades, as foundin standard #15 blades, or bigger blades, as founded in standard #20blades. In some embodiments, the tool head 150 of the retractable device110 can be any type of scalpel blades, i.e., the retractable device 110can be employed with any scalpel blade configuration.

In some embodiments, the retractable member 114 can be formed bysecurely attaching the tool head 150 to the support member 152 by a toolhead retention element 154 and a coupling element 156. As shown in FIGS.5A-C, the tool head retention element 154 can be configured to besecured to the tool head 150 at its front end and to the couplingelement 156 at its rear end. In such circumstances, the tool headretention element 154 can have a front portion to which the tool head150 is secured and a rear portion receivable in a bore of the couplingelement 156. The coupling element 156 can have a cylindrical bodyreceivable in a front end of the support member 152. The couplingelement 156 is in turn secured to a front end 158 of the support member152.

The tool head retention element 154 and the coupling element 156 can bestandard and universal which are able to receive most regular toolheads, such as regular scalpel blades.

It is to be understood that, in some embodiment, the tool head 150 isattached to the support member 152 by the tool head retention element154 and the coupling element 156 to form an inseparable structuralmember by fastening means such as solder, adhesive, or the like. Inother embodiments, the tool head 150 can be removably attached to thesupport member 152 by the tool head retention element 154 and thecoupling element 156, or other coupling mechanisms. It is to beunderstood that various mechanisms can be used for attaching the toolhead 150 to the support member 152.

FIGS. 6A-B illustrate perspective views of the support member 152 of theretractable member 114. FIG. 6C illustrates a cross-sectional view of alocking bridge of the support member 152 of FIG. 6A along line 6 c-6 c.FIG. 6D illustrates a rear end view of the support member 152. FIGS.7A-C illustrate cross sectional views of the support member 152. FIG. 7Aillustrates the support member 152 without the latch member 116 beingassembled therein. FIG. 7B illustrates the support member 152 with thelatch member 116 being assembled in the exposed position. FIG. 7Cillustrates the support member 152 with the latch member 116 beingassembled in the guarded position.

As shown in FIGS. 6A-B and 7A-C, the support member 152 has an elongatedbody having the front end 158 and a rear end 160, with a rear wall 161located at the rear end 160. Referring to FIGS. 6A-B and 7A-C, in someembodiments, the support member 152 can have an upper limb bypass slot162 defined at a top side of the support member 152. The upper limbbypass slot 162 can have a front end 164, a rear end 166 and twoparallel edges extending in an axial direction between the front andrear ends 164, 166.

As shown in FIGS. 7B-C, the width defined between the parallel edges ofthe upper limb bypass slot 162 can be slightly greater than the width Wof the upper limb 120 of the latch member 116, thereby when the latchmember 116 is assembled in the support element 152, the width of theupper limb bypass slot 162 allows the upper limb bypass slot 162 toslide snugly past the upper limb 120 of the latch member 116. However,it is to be understood that the width of the upper limb bypass slot 162can be much larger than the width of the upper limb 120, as desired.

As shown in FIGS. 3A-B and 7A-C, in some embodiments, the front end 164and rear end 166 of the upper limb bypass slot 162 define a retractionstop and a projection stop for the latch member 116, respectively. Asshown in FIGS. 3A and 7B, when the retractable member 114 is in theexposed position, the release button 126 of the latch member 116 ispositioned in a vicinity of the rear end 166 of the upper limb bypassslot 162. As used in the embodiment depicted in FIGS. 3A-B and 7A-C, theterm “vicinity” means a distance ranging from about 0.10 inches to about0.60 inches, such as about 0.20 inches.

As shown in FIGS. 3B and 7C, when the retractable member 114 is in theguarded position, the release button 126 of the latch member 116 ispositioned to abut the front end 164 of the upper limb bypass slot 162.In such circumstances, the length of the upper limb bypass slot 162determines the retraction distance d_(R) (shown in FIG. 3B). For toolheads 150 having different lengths, the length and position of the upperlimb bypass slot 162 can vary to allow appropriate tool head deploymentand retraction. That is, the length and position of the upper limbbypass slot 162 can be configured to allow a suitable portion of theretractable member 114, for example, the entire tool head 150, to beexposed in the exposed position, and to allow the retractable member114, for example, the tool head 150, to be appropriately guarded withinthe sheath member 112. The position of the upper limb bypass slot 162relative to the front end 158 of the retractable member 114 allows usewith blades of different lengths.

In some embodiments, the retraction distance d_(R) may range from about0.5 inches to about 3.5 inches. In one example, the retraction distanced_(R) can be about 2 inches.

Referring to FIGS. 6A, 6C and 7A-C, the support member 152 includes alocking bridge 168 defining the rear end 166 on its front edge 170 anddefining at least a portion of the front edge of a detent apex receivingopening 172 on its rear edge 174. As shown in FIGS. 3A and 7B, in use,when the retractable member 114 moves to the exposed position, thelocking bridge 168 slides on the detent ramp 134 of the detent element132 of the latch member 116, thereby deflecting the upper limb 120 ofthe latch member 116 downwardly toward a bottom side of the retractablemember 114. After the rear edge 174 of the locking bridge 168 passes thedetent apex 133 of the detent element 132, the locking bridge 168 isreceived by the locking slot 130 of the latch member 116 and engagedwith the latch member 116, with the rear edge 174 of the locking bridge168 abutting the front surface 131 of the detent element 132 of thelatch member 116. In such circumstances, the locking bridge 168 of theretractable member 114 is captured or locked in the locking slot 130 ofthe latch member 116, and the detent element 132 of the latch member 116is received in the detent apex receiving opening 172.

In some embodiments, the detent apex receiving opening 172 can have alarger width compared to the width W of the upper limb 120 of the latchmember 116 to avoid the detent element 132 of the latch member 116contacting side edges of the detent apex receiving opening 172, therebyavoiding friction produced by the contact. In addition, the larger widthof the detent apex receiving opening 172 allows the front surface 131 ofthe detent element 132 of the latch member 116 to be in contact with thefront edge of the detent apex receiving opening 172 entirely. As shownin FIG. 6A, in some embodiments, the width of the detent apex receivingopening 172 is greater than the width of the upper limb bypass slot 162.

Referring to FIG. 6C, in some embodiments, the locking bridge 168 isbeveled or tapered when extending from the rear edge 174 toward thefront edge 170. In some embodiments, the locking bridge 168 has auniform thickness and only the front edge 170 is beveled or tapered. Thebeveled or tapered front edge 170 of the locking bridge 168 and thedetent ramp 134 of the detent element 132 of the latch member 116cooperate to allow a friction produced during the latching process, suchas a friction produced by the movement of the locking bridge 168 overthe detent ramp 134 of the detent element 132 of the latch member 116 tobe reduced. In some embodiments, the tapered edge has an angle τ rangingfrom about 10° to about 80°. In one example, the angle τ can be about30°.

As shown in FIGS. 6A and 7A-C, the rear end of the detent apex receivingopening 172 is connected with a detent travel opening 176. The detenttravel opening 176 is configured to allow the detent element 132 of thelatch member 116 to travel rearward. In such circumstances, the detenttravel opening 176 is configured to have a length L_(DT) (referring toFIG. 6A) that is long enough to allow the entire detent element 132 ofthe latch member 116 to pass through the lower side of the lockingbridge 168 of the support member 152 until the upper limb 120 of thelatch member 116 flexes back by the resilience of the latch member 116and the detent element 132 engages with the rear edge 174 of the lockingbridge 168 at its front surface 131.

Referring to FIG. 6A, in some embodiments, the detent travel opening 176can have a smaller width than the width of the detent apex receivingopening 172. For example, the width of the detent travel opening 176 canbe generally the same as the width of the upper limb bypass slot 162,which is slightly greater than the width W of the upper limb 120 of thelatch member 116. However, it is to be understood that in someembodiments, the width of the detent travel opening 176 can be largerthan the width of the upper limb bypass slot 162.

Referring to FIGS. 6B, 6D, and 7A-C, in some embodiments, the supportmember 152 has a compression member bypass slot 146 at a bottom side ofthe support member 152 extending from the front end 158 to the rear end160, cutting through the rear wall 161 located at the rear end 160 ofthe support member 152. The compression member bypass slot 146 includesa bottom wall slot 147 at a bottom side of the support member 152 and arear wall slot 148 defined in the rear wall 161 that allow the bottomwall and the rear wall 161 to bypass a compression member 180 located onthe sheath member 112.

Still referring to FIGS. 6B and 7A-C, the bottom wall slot 147 has apair of parallel edges extending axially between the front end 158 andthe rear end 160 of the support member 152. A width of the bottom wallslot 147 is defined between the two parallel edges. The shape of therear wall slot 148 can be determined by the shape of the compressionmember 180 located on the sheath member 112 (described in more detailbelow in connection with FIGS. 8A-D).

Referring to FIGS. 6B and 7A-C, in some embodiments, the bottom wallslot 147 can include a lower limb bypass slot 159 for the lower limb 122of the latch member 116 to pass through. In such circumstances, thelower limb bypass slot 159 works with the upper limb bypass slot 162 toallow the latch member 116 to slide between the guarded position and theexposed position relative to the retractable member 114.

In the depicted embodiment, the rear end 163 of the lower limb bypassslot 159 can be located generally below the locking bridge 168 or at arear side of the locking bridge 168 (also comparing between FIGS. 6A-B),allowing the latch member 116 to travel rearward until the detentelement 132 is engaged with the locking bridge 168. It is to beunderstood that although in the embodiment depicted in FIGS. 6A-B and7A-C, the lower limb bypass slot 159 does not have a front end, thelower limb bypass slot 159 can in fact include a front end located at afront side of the front end 164 of the upper limb bypass slot 162.

In some embodiments, the lower limb bypass slot 159 can have a lengthranging from about 2 inches to about 4 inches. In one example, thelength of the lower limb bypass slot 159 can be about 3 inches.

Still referring to FIGS. 6B and 7A-C, in some embodiments, the lowerlimb bypass slot 159 can include a biasing member introduction slot 149for introduction of the biasing member 118. In the depicted embodiment,a front end 157 of the biasing member introduction slot 149 is locatedat a rear side of the front end 164 of the upper limb bypass slot 162(also comparing between FIGS. 6A-B). It is to be understood that thebiasing member introduction slot 149 can be located at various locationsalong the bottom wall slot 147.

In some embodiments, the biasing member introduction slot 149 can have alength ranging from about 0.30 inches to about 2.50 inches. In oneexample, the length of the biasing member introduction slot 149 can beabout 0.80 inches. In some embodiments, the length of the biasing memberintroduction slot 149 is configured to be as small as possible todecrease the chance of disfigurement of the biasing member 118 duringcompression, as long as the length of the biasing member introductionslot 149 is great enough for introduction of the biasing member 118.This can help reduce uneven compression of the biasing member 118.

It is to be understood that the biasing member introduction slot 149 canbe located at various locations along the length of the bottom wall slot147 as long as when the retractable member 114 is in the guardedposition, at least a portion of the biasing member introduction slot 149can be exposed outside the sheath member 112 for assembling the biasingmember 118 in the retractable member 114.

In some embodiments, in the exposed position, the biasing memberintroduction slot 149 is completely covered by the sheath member 112. Inother embodiments, as shown in FIG. 3B, in the guarded position, thebiasing member introduction slot 149 is completely exposed outside thesheath member 112 for easy introduction of the biasing member 118.

Referring to FIG. 6B, in some embodiments, the bottom wall slot 147 mayhave different width defined between its parallel edges. In the depictedembodiments, a smallest width of the bottom wall slot 147 can be assmall as slightly greater than the thickness of a lower end 192 of thecompression member 180 (referring to FIG. 3), which connects thecompression member 180 to an inner surface of the sheath member 112,thereby allowing the bottom wall slot 147 to slide past the compressionmember 180 of the sheath member 112. The section of the lower limbbypass slot 159 of the bottom wall slot 147 can have a larger widthwhich is slightly greater than the width W of the lower limb 122 of thelatch member 116, allowing the lower limb bypass slot 159 to slidesnugly past the lower limb 122 of the latch member 116. The section ofthe biasing member introduction slot 149 of the lower limb bypass slot159 can have the largest width which is the same as, or slightly smallerthan, the diameter of the biasing member 118, which allows introductionof the biasing member 118. However, it is to be understood that therelative sizes of different sections of the bottom wall slot 147 canvary. For example, in some embodiments, the width of the section of thelower limb bypass slot 159 can be the smallest among the differentsections. In some embodiments, the different sections of the bottom wallslot 147 can have a uniform width.

Referring to FIGS. 6B and 7A-C, in some embodiments, a rear end 165 ofthe biasing member introduction slot 149 is located at a front side ofthe rear end 163 of the lower limb bypass slot 159. However, thelocations of the biasing member introduction slot 149 relative to thelower limb bypass slot 159 can vary (described in more detail below inconnection with FIG. 10).

The dimension of the rear wall slot 148 of the compression member bypassslot 146 can vary as long as the rear wall slot 148 can slide past thecompression member 180 located on the sheath member 112 (described inmore detail below in connection with FIGS. 8A-D). In the embodimentdepicted in FIGS. 6A-B and 6D, the dimension of the rear wall slot 148of the compression member bypass slot 146 is slightly greater than thedimension of the compression member 180 located on the sheath member112, thereby allowing the rear wall slot 148 to slide past thecompression member 180.

Referring now to FIGS. 8A-C, in some embodiments, the sheath member 112has an elongated body having a front end 185 of the sheath member 112, arear end 189 of the sheath member 112 and a length defined between thefront end 185 of the sheath member 112 and the rear end 189 of thesheath member 112. In some embodiments, the sheath member 112 includes alatch introduction slot 167 defined at a top side of the sheath member112. The latch introduction slot 167 has a front end 169, a rear end 171and a length defined between the front end 169 and the rear end 171. Insome embodiments, the length of the latch introduction slot 167 isgreater than the entire length of the latch member 116 (referring toFIGS. 3A-B).

Referring to FIG. 8B, when the retractable member 114 is in the exposedposition, the latch introduction slot 167 of the sheath member 112 canbe located in a location such that at least a portion of the latchintroduction slot 167 is overlapped with the upper limb bypass slot 162of the retractable member 114. In such circumstances, the rear end 171of the latch introduction slot 167 can be positioned at a front side ofthe rear end 166 of the upper limb bypass slot 162. The overlap of thelatch introduction slot 167 and the upper limb bypass slot 162 allowsthe latch member 116 to be inserted in the retractable member 114through these slots. In some embodiments, the front end 169 of the latchintroduction slot 167 is located on a rear side of the front end 164 ofthe upper limb bypass slot 162 (referring to FIG. 3A), thereby providingan opening passing through the entire latch introduction slot 167 andthe upper limb bypass slot 162. As a result, the latch introduction slot167 of the sheath member 112 and the upper limb bypass slot 162 of theretractable member 114 can be positioned to allow a longer overlappedopening section for a more convenient insertion of the latch member 116.

As shown in FIG. 8A, the latch introduction slot 167 can have a widththat is generally the same as the width of the upper limb bypass slot162, which is slightly greater than the width W of the upper limb 120 ofthe latch member 116. However, it is to be understood that in someembodiments, the width of the latch introduction slot 167 can be greateror smaller than the width of the upper limb bypass slot 162, as long asthe width of the latch introduction slot 167 is greater than the widthof the upper limb 120 of the latch member 116.

Referring to FIGS. 8A-C, in some embodiments, the sheath member 112 mayinclude a latch button slot 173 located on the rear side of the latchintroduction slot 167. The latch button slot 173 can be configured toallow the release button 126 of the latch member 116 to protrudetherethrough, thereby maintaining the release button 126, and the latchmember 116 in turn, in a relatively fixed position to the sheath member112.

The latch button slot 173 can have a length and a width that areslightly greater than those of the release button 126, respectively,thereby allowing the release button 126 of the latch member 116 to bereceived in the latch button slot 173 snugly. However, it is to beunderstood that in some embodiments, the length and width of the latchbutton slot 173 can be much greater than those of the release button126, as desired.

Referring to FIGS. 8A-C, the rear end of the latch button slot 173 isdefined by a front edge 175 of a positioning bridge 177. In someembodiments, the front edge 175 of the positioning bridge 177 can beconfigured to have a greater width relative to a front portion of thelatch button slot 173. In such instances, the relatively wide front edge175 of the positioning bridge 177 provides a flat edge that cancooperate with the inclined button ramp 127 of the release button 126 ofthe latch member 116, while avoiding the friction occurring between therelease button 126 of the latch member 116 and the left and right edgesof the latch button slot 173. When the retractable device 110 is in theexposed position as shown in FIG. 8B, the front edge 175 of thepositioning bridge 177 is positioned to abut the inclined button ramp127 of the release button 126 of the latch member 116.

As shown in FIGS. 8A-C, in some embodiments, the positioning bridge 177is configured to be engaged with a top surface of the positioning step128 of the latch member 116, at least when the retractable member 114 isnot in the exposed position (referring to FIG. 8C). This helps limit theupper limb 120 of the latch member 116 from moving upwardly. In suchinstances, the positioning bridge 177 helps limit the upward movement ofthe detent element 132, thereby allowing the locking bridge 168 to slideon the detent ramp 134 of the latch member 116 smoothly, right beforethe detent element 132 engages with the locking bridge 168 and theretractable member 114 moves into the exposed position.

Referring to FIGS. 8A-C, in some embodiments, a sheath detent opening179 can be formed on a rear side of the positioning bridge 177 to allowa full upward movement of the detent element 132 of the latch member116. This can help ensure a firm locking between the detent element 132and the locking bridge 168. In the embodiment depicted in FIGS. 8A-C,the sheath detent opening 179 can have a contour that generally tracksthe entire contour of the detent apex receiving opening 172 and thedetent travel opening 176 defined in the retractable member 114. In someembodiments, the length of the sheath detent opening 179 can be shorterthan the total length of the detent apex receiving opening 172 and thedetent travel opening 176. However, it is to be understood that theshape of the sheath detent opening 179 can vary as long as the openingis large enough to allow a full upward movement of the detent element132 of the latch member 116.

Referring to FIGS. 8A-D, in some embodiments, the sheath member 112 canhave the compression member 180 as mentioned above extending rearwardfor compressing and in some embodiments centralizing the biasing member118. In such circumstances, the compression member 180 can be integrallyformed on the inner surface of the sheath member 112 at its lower end192. However, it is to be understood that the compression member 180 canalso be fabricated separately and attached to the inner surface of thesheath member 112 at its lower end 192. In some embodiments, the largestdiameter d_(CE) of the compression member 180 is configured to allow thecompression member 180 to be engageable with the biasing member 118.

Referring to FIGS. 9A-D, in some embodiments, when the biasing member118 takes the form of a spring, the compression member 180 can have atapered shape for even compression of the biasing member 118 during thecompression process. In such circumstances, the compression member 180can help reduce the friction occurred between the biasing member 118 andthe inner wall surface of the retractable member 114, and help avoiddeformation such as bulging of the biasing member 118.

Still referring to FIGS. 9A-D, in some embodiments, the compressionmember 180 can have a symmetrically-tapered shape to help further reducethe friction occurred between the biasing member 118 and the inner wallsurface of the retractable member 114, and help further avoiddeformation such as bulging of the biasing member 118. Thesymmetrically-tapered shape can be a cone shape, a pyramid shape, anarrow shape, or the like. The compression member 180 is axially orientedin the sheath member 112, with its axis substantially overlapping withthe longitudinal axis of the sheath member 112.

The symmetrically-tapered compression member can have variousconfigurations. In the embodiment depicted in FIGS. 8A-D and 9A, thecompression member 180 includes a tapered structure, e.g., anarrow-shaped plate, for engagement with a front end 139 of the biasingmember 118. The symmetrically-tapered sides 187 of the compressionmember 180 can help evenly distribute the force at least partially overthe inner periphery of the front end 139 of the biasing member 118. As aresult, the symmetrically-tapered sides help keep the biasing member 118centered on the compression member 180, when the biasing member 118 passaround the tapered sides.

FIG. 9B shows a compression member 1180 that extends less rearward thanthe compression member 180 in FIGS. 8A-D and 9A. FIG. 9C shows acompression member 2180 that extends more rearward than the compressionmember 180 in FIGS. 8A-D and 9A. FIG. 9D shows a compression member 3180that does not have a sharp rear end, for example, having a trapezoidalshape. It is to be understood that the compression member can have anon-tapered shape, such as a cylindrical shape, or the like, as long asit is engageable with the biasing member 118.

In the embodiment depicted in FIGS. 8A-C and 9A, the compression member180 can have an engagement mechanism 184 for engaging with a front end139 of the biasing member 118. In some examples, when the biasing member118 takes the form of a spring, the engagement mechanism 184 can includean upper flange and a lower flange formed at the two opposite edges ofthe tapered structure along the largest diameter d_(CE) of thecompression member 180. In such circumstances, the upper and lowerflanges not only allow front end 139 of the biasing member 118 to beseated on the flanges, but also help achieving even compression of thebiasing member. As a result, friction between the biasing member 118 andthe inner surface of the support member 152 can be minimized.

In some embodiments, the diameter of the base portion of the taperedstructure can be slightly smaller than the diameter of the biasingmember 118, thereby allowing the end of the biasing member 118 to engagewith the engagement mechanism 184, for example, the upper and lowerflanges, of the compression member 180. In the embodiments when thecompression member 180 includes a central pyramidal element, theengagement mechanism 184 can be a flange extending radially outwardlyfrom the central pyramidal element for engagement with the biasingmember 118.

In some embodiments, a gap 190 can be formed between the compressionmember 180 and the inner surface of the sheath member 112 for allowingthe locking bridge 168 to pass the compression member 180 and slide onthe detent ramp 134 of the latch member 116. This can gap allows a wallof the retractable member 114 to pass through the entire length of thesheath member 112. The size of the gap 190 can be slightly greater thanthe thickness of the side wall of the retractable member 114. In someembodiments, the size of the gap 190 may range from about 0.01 inches toabout 0.10 inches. In one example, the gap 190 can be about 0.05 inches.The dimension of the rear wall slot 148 formed on the retractable member114 is configured to slide past the compression member 180 to allow easyassembly.

Referring to FIG. 8A, an outer surface of the sheath member 112 mayinclude surface roughening 188 toward its front end, such as frictiongrooves, so that the user can easily grab or control the retractabledevice 110 during use. The surface roughening 188 can help preventslippage of user's fingers during use of the retractable device 110. Itis to be understood that the type and location of the surface rougheningcan vary as long as it can help prevent slippage of user's fingers.

Referring back to FIGS. 2 and 3A-B, the retractable device 110 mayinclude the biasing member 118, such as, but not by way of limitation, aspring, elastic, resilient, or compressible element or material. In suchcircumstances, the biasing member 118 can be disposed on a rear side ofboth the tool head 150 and the latch member 116. This allows a longretraction distance d_(R) (shown in FIG. 3B) without having to move thelatch member 116 relative to the sheath member 112. However, it is to beunderstood that the biasing member 118 can be positioned between thetool head 150 and the latch member 116 or at other locations.

In some embodiments, the basing member 118 can be disposed between therear end 160 of the support member 152 and a rear portion of the sheathmember 112. In such circumstances, the biasing member 118 can configuredto bias against an engagement portion of the sheath member 112, e.g., asurface of the compression member 180. When in use, the biasing member118 is compressed or released between the compression member 180 of thesheath member 112 and the rear end 160 of the support member 152 whenthe retractable member 114 is slidably moved relative to the sheathmember 112.

In some embodiments, the biasing member 118 takes the form of a spring.In such circumstances, when in the exposed position, the biasing member118 is compressed to a fraction of its more relaxed length, thusallowing a lengthy blade excursion. For example, as shown in FIGS. 3A-B,in some embodiments, a length of the compressed biasing member 118(referring to FIG. 3A) is no more than ½ of the length of the morerelaxed length of the biasing member 118 (referring to FIG. 3B).

In some embodiments, the biasing member 118 can be configured to causethe retractable member 114 to retract rapidly once the retractablemember 114 is released from the engagement with the detent element 132of the latch member 116. In such circumstances, the biasing member 118,such as a spring, can have a sufficiently great compression constantsuch that the biasing member 118 can cause the retractable member 114 toretract rapidly. In some examples, the biasing member 118 has acompression constant ranging from about 1.5 N/cm to about 3.5 N/cm.

In some embodiments, given that the biasing member 118 is compressed bya retraction distance d_(R), a force contributed by the biasing member118 may range from about 15.0 N to 35.0 N. In one example, the force ofthe compressed biasing member 118 in the retractable member 114 when theretractable member 114 is positioned in the guarded position can beabout 22.0 N. When the biasing member 118 is installed in theretractable member 114, the biasing member 118 is visible from outsidethrough the upper limb bypass slot 162 and the bottom wall slot 147.

Referring to FIG. 10A, to assemble the retractable device 110, the rearend 160 of the retractable member 114 can be inserted into the openingat the front end 185 of the sheath member 112, with the upper limbbypass slot 162 of the retractable member 114 aligned with the latchintroduction slot 167 of the sheath member 112. The retractable member114 can then be slidably moved toward the rear end 189 of the sheathmember 112 during which the rear wall slot 148 formed in the rear wall161 of the retractable member 114 slides past the compression member 180on the sheath member 112, and the top wall of the retractable member 114slides past the gap 190. When the rear end 166 of the upper limb bypassslot 162 of the retractable member 114 slides past the rear end 171 ofthe latch introduction slot 167 of the sheath member 112, the upper limbbypass slot 162 can be lined up with the latch introduction slot 167.The latch member 116 can then be introduced from the overlapped slots167, 162 into the interior space of the retractable member 114. The rearend 160 of the retractable member 114 can then be pushed forward,allowing the top surface 129 of the release button 126 to abut the innerwall surface on the top side of the sheath member 112 and the lower endof the 144 of the latch member 116 to abut the inner wall surface of thebottom side of the sheath member 112.

The assembler can then pull the rear end 160 of the retractable member114 rearward until the front end 164 of the upper limb bypass slot 162engages with the front surface 125 of the release button 126 of thelatch member 116, and then pull the retractable member 114 furtherrearward, pushing the latch member 116 to move rearward until therelease button 126 of the latch member 116 snaps through the latchbutton slot 173 of the sheath member 112 due to the resilience force ofthe latch member 116, as shown in FIG. 10B. As a result, the releasebutton 126 is self-secured in the button slot 173 of the sheath member112, as a permanent location. In such circumstances, the detent element132 of the latch member 116 is visible from above the sheath detentopening 179 of the sheath member 112.

The assembler then turns around the retractable device 110, allowing thebottom side of the retractable device 110 to face the assembler, withthe biasing member introduction slot 149 at least partially exposedoutside of the sheath member 112. The assembler can then insert andforce the spring into the biasing member introduction slot 149.

The retractable device 110 can be disassembled following a reverseprocedure of the assembling process of the retractable device 110.

In some embodiments, the tool head 150 can be replaced by any type oftool heads, such as various types of standard scalpel blades. Inreplacing the tool head 150, the tool head 150 is simply removed fromfront end of the tool head retention element 154.

When the retractable device 110 is in use, as depicted in FIG. 3A, insome embodiments, the retractable member 114 is pushed forward, allowingthe tool head 150 to extend out from the front end of the sheath member112 in the exposed position. The biasing member 118 is compressedaccordingly. The locking bridge 168 of the support member 152 movesforward relative to the sheath member 112 until contact is made with thedetent ramp 134 of the latch member 116. The locking bridge 168 of thesupport member 152 thus depresses the detent 132 of the latch member 116downwardly. At the end of its travel, the locking bridge 168 of thesupport member 152 then contacts the locking slot 130. The resilienceforce of the latch member 116 disposes the upper limb 120 of the latchmember 116 upwardly, thereby locking the retractable member 114 in itsexposed position.

After locking, the sheath detent opening 179 defined in the sheathmember 112 is then in position directly over the detent apex receivingopening 172 of the support member 152, thereby allowing an unencumberedupward travel of the detent 132 of the latch member 116 through bothslots to achieve secure locking. When the retractable device 110 is notin use, the release button 126 of the latch member 116 is pressed, andthe locking bridge 168 of the retractable member 114 is released fromthe engagement with the detent element 132 of the latch member 116 so asto allow the longitudinal movement between the sheath member 112 and theretractable member 114. The biasing force of the biasing member 118 ofthe support member 152, such as a compressed force of a spring, theninstantly retracts the retractable member 114, rendering the tool head150 covered by the sheath member 112.

The deployment and retraction sequence of the retractable device 110 hasto be smooth and unencumbered by friction between the biasing member 118and the inner wall surface of the support member 152. This smooth actionis allowed by the coupling between the compression member 180 and afront end of the biasing member 118.

FIG. 11 shows a further embodiment of a support member 252 of theretractable member 214. The support member 252 has a similarconfiguration as the support member 152 except that a biasing memberintroduction slot 249 is located at a different location relative to thelower limb bypass slot 159 shown in FIGS. 6B and 7A-C.

As shown in FIG. 11, the support member 252 has a bottom wall slot 247configured to allow the bottom wall of the support member 252 to bypassa compression member located on a sheath member. The support member 252further has a lower limb bypass slot 259 configured to slide past alower limb of a latch member when the retractable member moves betweenan exposed position and a guarded position relative to the sheathmember. In the embodiment depicted in FIG. 11, a rear end 278 of thebiasing member introduction slot 249 is connected directly with thebottom wall slot 247 instead of being connected with the lower limbbypass slot 259. Only the front end 257 of the biasing memberintroduction slot 249 is connected to the lower limb bypass slot 259. Insuch circumstances, the biasing member introduction slot 249 is at leastpartially exposed from the sheath member when the retractable member ispositioned in both the exposed position and the guarded position. It isto be understood that the biasing member introduction slot 249 can belocated at other locations relative to the lower limb bypass slot 259and the bottom wall slot 247.

FIGS. 12A-B show a further embodiment of a sheath member 312. The sheathmember 312 has a similar configuration as the sheath member 112 exceptthat the sheath member 312 has a tool head maintaining mechanism 378. Insuch circumstances, the tool head maintaining mechanism 378 can beconfigured for safeguarding the tool head within the space defined by anouter wall surface 386 of the sheath member 312 without increasing thediameter of the sheath member 312.

In some embodiments, the tool head maintaining mechanism 378 can includea pair of longitudinally extending, diametrically opposed slots at afront portion of the sheath member 312. In some embodiments, the slotscan include a top tool head slot 381 disposed at a top side of thesheath member 312 and a bottom tool head slot 383 disposed at a bottomside of the sheath member 312.

This configuration allows the retractable device to be used with a toolhead that has a width slightly larger than the diameter of an inner wallsurface 382 of the sheath member 312. The top slot 381 and the bottomslot 383 can be configured to allow a cutting edge of a larger toolhead, such as a surgical blade, to be safely guarded in the sheathmember 312, thereby protecting the tool head from accidental contact orinjury to another person.

Referring to FIGS. 13A-E, in some embodiments, a retractable device 410can include a locking mechanism 445 to prevent a retractable member 414from moving axially relative to a sheath member 412, when theretractable device 410 is positioned in the guarded position. Forexample, as shown in FIG. 13A, the locking mechanism 445 can be actuatedby rotating the retractable member 414 relative to the sheath member 412so as to lock the retractable member 414 axially relative to the sheathmember 412, preventing the retractable member 414 from moving forward.The locking mechanism 445 can be released by counter-rotating theretractable member 414 relative to the sheath member 412. It is to beunderstood that the locking mechanism 445 can have other configurationsas long as it can prevent axial movement of the retractable member 414relative to a sheath member 412.

Referring to FIGS. 13B-C, the locking mechanism 445 can include cutoutsformed on a support member 452 of the retractable member 414. Forexample, the locking mechanism 445 can include an upper limb cutout 443formed on a left side of an upper limb bypass slot 462. The upper limbcutout 443 has a front end shoulder 494 located in a vicinity of a frontend 458 of the slot 462, when viewed from above the upper limb bypassslot 462. In some embodiments, the term “vicinity” can mean a distancesimilar to or less than a width W_(US) of the upper limb bypass slot462.

The upper limb cutout 443 can have a width W_(UC) configured to beslightly greater than a width W of the upper limb of a latch member 416installed in the retractable member 414, similar to the width W_(US) ofthe upper limb bypass slot 462. The length of the upper limb cutout 443can be slightly longer than the distance between a front surface 425 ofa release button 426 and a detent apex 433 of a detent element 432 ofthe latch member 416. It is to be understood that the width W_(UC) andthe length of the upper limb cutout 443 can vary as long as the upperlimb cutout 443 is large enough to receive the release button 426 and atleast part of the detent element 432 in a locked position as shown inFIG. 13A.

It is to be understood that the particular shape and location of theupper limb cutout 443 can vary. For example, the cutout 443 can belocated on the right side, instead of the left side, of the upper limbbypass slot 462. The cutout 443 can also be located at other locationsrelative to the upper limb bypass slot 462, as long as the location andthe shape of the cutout 443 allow the latch 416 to be received in thecutout 443, when the retractable member 414 is rotated relative to thesheath member 412.

Referring to FIGS. 13D-E, the locking mechanism 445 can also include alower limb cutout 491 and a compression member cutout 493 formed on aleft side of a lower limb bypass slot 459, when viewed from above thelower limb bypass slot 459. In such circumstances, the front end of thelower limb cutout 491 can be located on a slightly rear side of thefront end of the upper limb cutout 443 to thereby receive a balancingelement 440 of the latch member 416 when the retractable member 414 isin the locked position as shown in FIG. 13A.

The compression member cutout 493 is located on a rear side of the lowerlimb cutout 491. The compression member cutout 493 is configured toreceive the lower end of a compression member (the lower end of thecompression member is not shown in FIGS. 13A-E; referring to the lowerend 192 in a similar embodiment in FIGS. 3A-B) formed on an innersurface of the sheath member 412, when the retractable member 414 is inthe locked position.

Still referring to FIGS. 13D-E, the lower limb cutout 491 and thecompression member cutout 493 can have a width slightly greater than awidth W of the lower limb of the latch member 416 installed in theretractable member 414. The length of the lower limb cutout 491 can varyas long as it can snugly receive the balancing element 440. The lengthof the compression member cutout 493 can vary as long as it can snuglyreceive the lower end of the compression member of the sheath member412.

It is to be understood that the particular location of the lower limbcutout 491 and the compression member cutout 493 can vary. For example,the cutouts 491, 493 can be located on the right side, instead of theleft side, of the lower limb bypass slot 459. The cutouts 491, 493 canalso be located at other locations relative to the lower limb bypassslot 459, as long as the location and the shape of the cutouts 491, 493allow the balancing element 440 of the latch 416 and the lower end ofthe compression member to be received in the cutouts 491, 493,respectively, when the retractable member 414 is rotated relative to thesheath member 412.

It is to be understood that the width of the upper limb cutout 443, thewidth of the lower limb cutout 491 and the width of the compressionmember cutout 493 can vary. When the width of the upper limb cutout 443,the width of the lower limb cutout 491 and the width of the compressionmember cutout 493 are greater, the retractable member 414 can be rotateda greater angle relative to the sheath member 412. When the width of theupper limb cutout 443, the width of the lower limb cutout 491 and thewidth of the compression member cutout 493 are smaller, the retractablemember 414 can be rotated less relative to the sheath member 412. Insome embodiments, the retractable member 414 is configured to rotate 30°relative to the sheath member 412. In other embodiments, the retractablemember 414 is configured to rotate less than 30°, such as 15° relativeto the sheath member.

Referring to FIG. 13A, to actuate the locking mechanism 445 of theretractable device 410, the retractable member 414 can be rotatedcounter-clockwise relative to the sheath member 412 (when viewed fromthe front side of the retractable member 414), when the retractabledevice 410 is positioned in a guarded position. In such circumstances,the upper limb cutout 443 is aligned with the release button slot 473.As a result, the retractable member 414 is locked axially relative tothe sheath member 412, preventing the retractable member 414 from movingforward. The locking mechanism 445 can be released by rotating theretractable member 414 clockwise (when viewed from the front side of theretractable member 414) to allow the release button 426 to be releasedfrom the upper limb cutout 443.

As shown in FIG. 13A-C, in some embodiments, the front end shoulder 494of the upper limb cutout 443 is located on a slightly rear side of thefront end 458 of the upper limb bypass slot 462 of the support member452. For example, the front end shoulder 494 of the upper limb cutout443 can be located 1/16 inches on the rear side of the front end 458 ofthe upper limb bypass slot 462.

To actuate the locking mechanism 445, the retractable device 410 isinitially positioned in the guarded position. The retractable member 414is then pushed slightly forward. Once the front end shoulder 494 of theupper limb cutout 443 of the retractable member 414 is aligned with thefront end 495 of a latch button slot 473 of the sheath member 412, theretractable member 414 is rotated counter-clockwise relative to thesheath member 412 (when viewed from the front side of the retractablemember 414) such that the upper limb cutout 443 is aligned with therelease button slot axially. As a result, the upper limb bypass slot 462of the support member 452 is rotated sideway and no longer aligned withthe release button slot 473 of the sheath member. The fact that thefront end shoulder 494 of the upper limb cutout 443 is located on a rearside of the front end 458 of the upper limb bypass slot 462 allows apositive engagement between the upper limb cutout 443 and the releasebutton 426. The locking mechanism 445 can be released by rotating theretractable member 414 clockwise (when viewed from the front side of theretractable member 414) to allow the release button 426 to be releasedfrom the upper limb cutout 443.

FIGS. 14A-F illustrate a retractable device 510 similar to theconfiguration of FIGS. 13A-E, except that a locking mechanism 545 of theretractable device 510 has a different design. As shown in FIGS. 14A-D,the locking mechanism 545 can include cutouts formed on a support member552 of a retractable member 514 and a locking status indicator 515. Itis to be understood that the locking mechanism 545 can have otherconfigurations as long as it can prevent axial movement of theretractable member 514 relative to a sheath member 512 and indicate thelocking status.

As shown in FIGS. 14C-D, the locking mechanism 545 can include an upperlimb cutout 543 formed on a left side of an upper limb bypass slot 562.The upper limb cutout 543 has a front end shoulder 594 formed byradially extending a front end 558 of the slot 562 toward a left side.When viewed from above the upper limb bypass slot 562, the front endshoulder 594 of the cutout 543 and the front end 558 of the slot 562 endat the same axial location on the retractable member 514.

The upper limb cutout 543 can have a width W_(UC) configured to beslightly greater than the width W of the upper limb of a latch member516 installed in the retractable member 514, similar to a width W_(US)of the upper limb bypass slot 562. The length of the upper limb cutout543 can be slightly longer than the distance between a front surface 525of a release button 526 and a detent apex 533 of a detent element 532 ofthe latch member 516. It is to be understood that the width W_(UC) andthe length of the upper limb cutout 543 can vary as long as the upperlimb cutout 543 is large enough to receive the release button 526 and atleast part of the detent element 532 in a locked position as shown inFIG. 14A-B.

It is to be understood that the particular location of the upper limbcutout 543 can vary. For example, the cutout 543 can be located on theright side, instead of the left side, of the upper limb bypass slot 562.The cutout 543 can also be located at other locations relative to theupper limb bypass slot 562, as long as the location and the shape of thecutout 543 allows the latch 516 to be received in the cutout 543, whenthe retractable member 514 is rotated relative to the sheath member 512.

Referring to FIGS. 14E-F, the locking mechanism 545 can also include alower cutout 591 formed on a left side of a lower limb bypass slot 559of the support member 552 of the retractable member 514, when viewedfrom above the lower limb bypass slot 559. In such circumstances, thefront end of the lower cutout 591 can be located on a slightly rear sideof the front end of the upper limb cutout 543, and the length of thelower cutout 591 can be configured to snugly contain both a balancingelement 540 of the latch member 516 and the lower end of a compressionmember formed on an inner surface of the sheath member 512 (the lowerend of the compression member is not shown in FIGS. 14A-F; referring tothe lower end 192 in a similar embodiment in FIGS. 3A-B), when theretractable member 514 is in the locked position as shown in FIG. 14A-B.

Still referring to FIGS. 14E-F, the lower cutout 591 can have a widthslightly greater than the width of the lower limb of the latch member516 installed in the retractable member 514 and the width of the lowerend of the compression member formed on the sheath member 512.

It is to be understood that the particular location of the lower cutout591 can vary. For example, the cutout 591 can be located on the rightside, instead of the left side, of the lower limb bypass slot 559. Thecutout 591 can also be located at other locations relative to the lowerlimb bypass slot 559, as long as the location and the shape of thecutout 591 allow the balancing element 540 of the latch 516 and thelower end of the compression member to be received in the cutout 591,when the retractable member 514 is rotated relative to the sheath member512.

It is to be understood that the width of the upper limb cutout 543 andthe width of the lower cutout 591 can vary. When the width of the upperlimb cutout 543 and the width of the lower cutout 591 are greater, theretractable member 514 can be rotated a greater angle relative to thesheath member 512. When the width of the upper limb cutout 543 and thewidth of the lower cutout 591 are smaller, the retractable member 514can be rotated less relative to the sheath member 512. In someembodiments, the retractable member 514 is configured to rotate 45°relative to the sheath member 512. In other embodiments, the retractablemember 514 is configured to rotate less than 45°, such as 30° or 15°relative to the sheath member.

With the width extension, the upper limb bypass slot 562 along with theupper limb cutout 543 can act as a biasing member introduction slot 549that allows a biasing member, such as a spring, to be introduced. Insuch circumstances, the length and width of the biasing memberintroduction slot 549 are configured to be as small as possible todecrease the chance of disfigurement of the biasing member duringcompression, as long as the length and width of the biasing memberintroduction slot 549 are great enough for introduction of the biasingmember. This can help reduce uneven compression of the biasing member.

Likewise, with the width extension, the lower limb bypass slot 559 alongwith the lower cutout 591 can act as a biasing member introduction slot549 that allows a biasing member, such as a spring, to be introduced. Insuch circumstances, the length and width of the biasing memberintroduction slot 549 are configured to be as small as possible todecrease the chance of disfigurement of the biasing member duringcompression, as long as the length and width of the biasing memberintroduction slot 549 are great enough for introduction of the biasingmember. This can help reduce uneven compression of the biasing member.

The locking mechanism 545 of the retractable device 510 depicted inFIGS. 14A-E includes a locking status indicator 515. The locking statusindicator 515 can be configured to indicate a status of the lockingmechanism 545, for example, whether the retractable device 510 is lockedin a guarded position. In some embodiments, the locking status indicator515 can be a reference component to which a user can refer to decide adetectable condition of the retractable device 510.

Referring to FIGS. 14C-D, in some embodiments, color coding can be usedas at least part of the locking status indicator 515. In the embodimentdepicted in FIGS. 14A-F, a front portion of the support member 552 ofthe retractable member 514 can be colored with a particular color, forexample, red, as a reference component 541 showing that the retractabledevice 510 has been locked. As shown in FIG. 14B, when the retractabledevice 510 is locked, the reference component 541 can be viewed throughthe upper limb bypass slot 562 of the sheath member 512. The colorcoding of the reference component 541 can indicate that the retractabledevice 510 is locked in the guarded position.

In some embodiments, as shown in FIGS. 14C-D, a further referencecomponent 551 can be indicated on the front portion of the supportmember 552 of the retractable member 514, next to the referencecomponent 541. The reference component 551 can include a differentcolor, for example, green, to indicate that the retractable device hasbeen unlocked. As shown in FIG. 14A, when the retractable device 510 isunlocked, the reference component 551 can be viewed through the upperlimb bypass slot 562 of the sheath member 512. The color coding of thereference component 551 can indicate that the retractable device 510 isunlocked.

It is to be understood that the particular color of the referencecomponents 541, 551 can vary as desired. It is also to be understoodthat in some embodiments, the reference component 551 is not needed toindicate the unlocked status.

In some embodiment, indicia can be used either alone or in combinationwith the color coding, as at least part of the locking status indicator515. For example, when red is used for the reference component 541 toindicate the retractable device 510 being in a locked status, theindicia “LOCKED” can be added as part of the reference component 541. Asa result, the reference component 541 includes both the color coding andthe indicia to show that the retractable device 510 has been locked. Insuch circumstances, the reference component 541, e.g., the indicia“LOCKED” in red color, can be viewed through the upper limb bypass slot562 of the sheath member 512.

Likewise, when green is used for the reference component 551 to indicatethe retractable device 510 being in an unlocked status, the indicia“UNLOCKED” can be added as part of the reference component 551. As aresult, the reference component 551 includes both the color coding andthe indicia to show that the retractable device 510 has been unlocked.In such circumstances, the reference component 551, e.g., the indicia“UNLOCKED” in green color, can be viewed through the upper limb bypassslot 562 of the sheath member 512.

Similar to the process depicted in FIG. 10A and the accompanying text,as shown in FIGS. 14A-F, to assemble the retractable device 510, therear end of the retractable member 514 can be inserted into the openingat the front end of the sheath member 512, with the upper limb bypassslot 562 of the retractable member 514 aligned with a latch introductionslot 567 of the sheath member 512. The retractable member 514 can thenbe slidably moved toward the rear end of the sheath member 512 duringwhich the rear wall slot formed in the rear wall of the retractablemember 514 slide past the compression member on the sheath member 512,and the top wall of the retractable member 514 slides past the gapformed between the compression member and the inner surface of thesheath member 512. When the rear end of the retractable member 514slides past the rear end of the sheath member and any of the biasingmember introduction slots 549 defined in the top or bottom wall of thesupport member 552 of the retractable member 514 is exposed, theassembler can then insert and force a biasing member, e.g., a spring,into the respective biasing member introduction slot 549.

The assembler can then push the rear end of the retractable member 514forward relative to the sheath member 512 until the front end of theupper limb bypass slot 562 of the retractable member 514 slides past therear end of the latch introduction slot 567 of the sheath member 512.The assembler can then align the upper limb bypass slot 562 with thelatch introduction slot 567 to allow the latch member 516 to beintroduced into the interior space of the retractable member 514 throughthe overlapped slots 567, 562.

The latch member 516 can then be pressed downwardly and rearward toallow the top surface of the release button 526 to abut the inner wallsurface on the top side of the sheath member 512 and the lower end ofthe latch member 516 to abut the inner wall surface of the bottom sideof the sheath member 512. The assembler can then pull the rear end ofthe retractable element 514 rearward until the front end of the upperlimb bypass slot 562 engages with the front surface of the releasebutton 526 of the latch member 516, and then pull the retractable member514 further rearward, pushing the latch member 516 to move rearwarduntil the release button 526 of the latch member 516 snaps through thelatch button slot 573 of the sheath member 512 due to the resilienceforce of the latch member 516, as shown in FIG. 14A. As a result, therelease button 526 is self-secured in the button slot 573 of the sheathmember 512, as a permanent location. In such circumstances, the detentelement 532 of the latch member 516 is visible to a viewer.

The retractable device 510 can be disassembled following a reverseprocedure of the assembling process of the retractable device 510.

Referring to FIGS. 14A-B, to actuate the locking mechanism 545 of theretractable device 510, the retractable member 514 can be rotatedcounter-clockwise relative to the sheath member 512 (when viewed fromthe front side of the retractable member 514), when the retractabledevice 510 is positioned in the guarded position. In such circumstances,the upper limb cutout 543 is aligned with the release button slot 573.As a result, the retractable member 514 is locked axially relative tothe sheath member 512, preventing the retractable member 514 from movingforward. The reference component 541 of the locking status indicator 515can be viewed by the user through the upper limb bypass slot 562 toindicate that the retractable device 510 is locked in the guardedposition. The locking mechanism 545 can be released by rotating theretractable member 514 clockwise (when viewed from the front side of theretractable member 514) to allow the release button 526 to be releasedfrom the upper limb cutout 543. In such circumstances, the referencecomponent 551 of the locking status indicator 515 can be viewed by theuser through the upper limb bypass slot 562 to indicate that theretractable device 510 is unlocked.

When used herein, the term “self-lock” or “self-locking” meansautomatically moving the retractable member to a position relative tothe sheath member to ensure the immovable retention of the retractablemember to the sheath member.

Referring to FIGS. 15, 16A-B, 17A-B, 18 and 19A-C, a further embodimentof the retractable device 610 includes a sheath member 612, aretractable member 614, a latch member 616 and a biasing member 618. Theretractable member 614 includes a tool head 650 and a support member 652that supports the tool head 650. The retractable member 614 is slidablerelative to the sheath member 612, such that the tool head 650 can bepositioned in an exposed position when the retractable member 614 islatched relative to the sheath member 612, as well as a guarded positionafter the latch is released.

Referring to FIG. 18, the retractable device 610 includes a self-lockingmechanism 645 configured to cause the retractable member 614 to beself-locked relative to the sheath member 612, when the latch betweenthe sheath member 612 and the retractable member 614 is released and theretractable member 614 retracts to the guarded position. Theself-locking mechanism 645 includes a guiding member 611, a top wallcutout 643 including a top cutout shoulder 603, and a bottom wall cutout691 including a bottom cutout shoulder 605 defined in the retractablemember 614, and a sliding member 613 formed on the sheath member 612.When the tool head 650 moves from the exposed position toward theguarded position in an axial direction, the sliding member 613 formed onthe sheath member 612 cooperates with the guiding member 611 formed onthe retractable member 614. As a result, the retractable member 614 isdriven to rotate relative to the sheath member 612. Once the retractablemember 614 reaches the guarded position, the latch member 616 andcompression member 680 are both automatically received in at least thetop wall cutout 643 and the bottom wall cutout 691, thereby self-lockingthe retractable member 614 in an axial direction relative to the sheathmember 612 by at least the bottom cutout shoulder 605.

Referring to FIG. 15, the sheath member 612 includes a latchintroduction slot 667, a latch button opening 673, a sheath detentopening 679 and a positioning bridge 677 between the latch buttonopening 673 and sheath detent opening 679. The sheath member 612 alsoincludes a compression member 680 extending rearward for compressing andin some embodiments centralizing the biasing member 618.

FIG. 15 includes not only the sheath member 612 but also the sheathmember 112 as shown in FIG. 8A for purpose of comparison. The sheathmember 612 has a similar configuration as the sheath member 112 of FIG.8A. Differences between the two sheath members include that the sheathmember 612 has a sliding member 613, while the sheath member 112 doesnot.

In the embodiment depicted in FIGS. 15, 16A-B, 18 and 19A-C, the slidingmember 613 takes the form of a sliding pin 609 extending upwardly from abottom wall of the sheath member 612. The sliding pin 609 can cooperatewith the guiding member 611 to translate the axial movement of theretractable member 614 to rotation. In one embodiment, the sliding pin609 has a diameter of 0.045 inches and a height of 0.125 inches. It isto be understood that the sliding member 613 can take other forms aslong as it can cooperate with the guiding member 611 on the retractablemember 614 to cause the retractable member 614 to translate theretraction movement of the retractable member 614 to rotation.

Comparing the sheath member 612 to the sheath member 112 in FIG. 15,another difference between the two is that the length of the latchintroduction slot 667 has been extended by a distance a to allow thelatch member 616 to be inserted between a rear end of the latchintroduction slot 667 and the sliding pin 609.

FIGS. 17A-B depict the retractable member 614 of the retractable device610. The retractable member 614 includes the tool head 650 and thesupport member 652 supporting the tool head 650. An upper limb bypassslot 662, a detent apex receiving opening 672, a detent travel opening676 and a locking bridge 668 that divides the upper limb bypass slot 662from the detent apex receiving opening 672 are formed on top of thesupport member 652.

A top wall cutout 643 is formed on a left side of the upper limb bypassslot 662. Optionally, the top wall cutout 643 has a top ramp 604 locatedat a rear end of the top wall cutout 643, with a center of the top ramp604 curved generally toward an axial center of the upper limb bypassslot 662. This curved top ramp 604 can guide a rear portion of the latchmember 616 to prompt the retractable member 614 to start rotating inaccordance with the retraction of the retractable member 614.

A top cutout shoulder 603 is formed at the front end of the top ramp 604to prevent the retractable member 614 from sliding forwardly if anoutside force is applied to push the retractable member 614 forwardly.The top cutout shoulder 603 can engage with a rear portion of the latchmember 616 to lock the retractable member 614 in the guarded position.

At the bottom of the retractable member 614, a lower limb bypass slot659, a biasing member introduction slot 649 and a bottom wall slot 647are formed at a bottom side of the support member support member 652.

A bottom wall cutout 691 is formed on a left side of the lower limbbypass slot 659 when viewed from above the bottom wall of theretractable member 614. Optionally, the bottom wall cutout 691 has abottom ramp 606 located at a rear end of the bottom wall cutout 691,with a center of the bottom ramp 606 curved generally toward an axialcenter of the lower limb bypass slot 659. This curved bottom ramp 606can work with the curved top ramp 604 to prompt the retractable member614 to start rotating in accordance with the retraction of theretractable member 614.

A bottom cutout shoulder 605 is formed at the front end of the bottomramp 606 to prevent the retractable member 614 from moving forwardly ifan outside force is applied to push the retractable member 614forwardly. The bottom cutout shoulder 605 can engage with a portion ofthe compression member 680 to lock the retractable member 614 in theguarded position.

As shown in FIGS. 17A-B, in the embodiment depicted in the figures, thetop wall cutout 643 and the bottom wall cutout 691 are configured toface each other across an axial axis of the retractable member 614. Insome embodiments, the top ramp 604 and the bottom ramp 606 can beconfigured to also face each other across the axial axis. It is to beunderstood that the top wall cutout 643 and the bottom wall cutout 691can each be a cutout formed on a right side, instead of the left side,of the respective slot. The specific configuration of the cutouts, suchas the shape of the cutouts, the number of the cutouts can vary as longas the cutouts can receive both the latch member 616 and the compressionmember 680 to allow rotation of the retractable member 614. In oneexample, a diameter of the sliding pin 609 is smaller than the width ofthe lower limb bypass slot 659, the biasing member introduction slot 649and the bottom wall slot 647 at a bottom side of the support membersupport member 652, respectively.

The retractable member 614 can further include a guiding member 611 thatcan cooperate with the sliding member 613 of the sheath member 612 totranslate the axial movement of the retractable member 614 to rotation.In one example, the guiding member 611 takes the form of a clockwisespiral guiding groove 607 extending from a front end of the upper limbbypass slot 662 upwardly and forwardly toward the tool head 650 on aright side of the retractable member 614. In the example depicted in thedrawings, the guiding groove 607 is ¼ of a helical revolution. In oneexample, the guiding groove 607 extends from an axial center of theretractable member and is positioned perpendicular to the longitudinalaxis of the retractable member in any cross section of the retractablemember 614.

When the tool head 650 moves from the exposed position toward theguarded position, the sliding pin 609 formed on the sheath member 612slides along a surface of the guiding groove 607. In such circumstances,the surface of the guiding groove 607 guides the sliding pin 609, whenthe retractable member 614 retracts toward the guarded position. This inturn drives the retractable member 614 to rotate relative to the sheathmember 612. Once it reaches the guarded position, the retractable member614 is self-locked relative to the sheath member 612 in an axialdirection. The retractable member 614 also includes a rear wall slot 648defined in a rear wall 661 of the retractable member 614. In theembodiment depicted in FIGS. 15, 16A-B, 17A-B, 18 and 19A-C, the guidinggroove 607 can cooperate with the sliding pin 609 to drive theretractable member 614 to rotate at an angle of about 90 degrees.

It is to be understood that the guiding member 611 can take other forms,such as other shapes, as long as it can cooperate with the slidingmember 613 on the retractable member 614 to cause the retractable member614 to translate the axial retraction movement of the retractable member614 to rotation. It is also to be understood that the location and thespecific configuration of the guiding groove 607 can vary depending onhow much rotation is intended. In some examples, the self-lockingmechanism 645, shown in FIG. 18, which includes the sliding pin 609 andguiding groove 607, can be configured to drive the retractable member614 to rotate at an angle ranging from 10 degrees to 135 degrees. Inother examples, the angle can range from 30 degrees to 100 degrees.

In some embodiments, the guiding groove 607 can be located on otherportions of the outer surface of the front portion of the retractablemember 614. For example, the guiding groove can be located on the outersurface of the top, the left or the bottom of the retractable member614. Accordingly, the sliding pin 609 can formed on different portionsof the inner side wall of the sheath member 612, such as the right sidewall, the top wall or the left side wall to correspond to the top, theleft or the bottom of the outer surface of the retractable member 614,respectively. It is to be understood that the guiding groove 607 canhave a sharper turn or wider turn to achieve a greater rotation angle ora smaller rotation angle of the retractable member 614 relative to thesheath member 612, respectively. In addition, the biasing member 618,such as a spring, can have greater strength or less strength to allowthe sliding pin 609 to advance in the respective sharper turn guidinggroove or wider turn guiding groove.

Referring to FIG. 18, to assemble the retractable device 610, a rear endof the retractable member 614 can be inserted into an opening at a frontend of the sheath member 612, with the upper limb bypass slot 662 of theretractable member 614 aligned with the latch introduction slot 667 ofthe sheath member 612. The retractable member 614 can then be slidtoward the rear end of the sheath member 612 during which the rear wallslot 648 formed on the rear wall 661 of the retractable member 614slides past the compression member 680 formed on the sheath member 612,and the top wall of the retractable member 614 slides past a gap 690formed between a top portion of the compression member 680 and the innersurface of the support member 652. When the rear end of the upper limbbypass slot 662 is aligned with the rear end of the latch introductionslot 667, the latch member 616 can then be introduced from theoverlapped slots 667, 662 into the interior space of the retractablemember 614.

As shown in FIGS. 15 and 18, the latch introduction slot 667 is extendedby a distance a relative to the latch introduction slot 167 to allow thelatch member 616 to be inserted between the sliding pin 609 and the rearend of the latch introduction slot 667 in the axial direction. Asdepicted in FIG. 18, the sliding pin 609 is spaced apart from a rear endof the latch introduction slot 667 by an axial distance b, for example,an axial distance that is slightly longer than a length of an armsegment 621 of the upper limb 620 of the latch member 616 plus a lengthof a release button 626 of the latch member 616. In such circumstances,when the latch member 616 is inserted between the rear end of the latchintroduction slot 667 and the sliding pin 609, a front end of the latchmember 616 is spaced apart from the sliding pin 609 by a distance b. Inone example, the axial distance b ranges between about 0.005 inches andabout 0.200 inches.

Still referring to FIG. 18, in one example, the retractable member 614further includes a step 602 acting as a stopper at its front end toengage with a front end of the latch member 616 to stop rotation of theretractable member.

Once the latch member 616 is put in place, the biasing member 618 can beinserted in the interior space of the retractable member 614 by aprocess similar to those described in the above embodiments. Once thebiasing member 618 is inserted, the assembling process of theretractable device 610 is complete. The retractable device 610 can bedisassembled following a reverse procedure of the assembling process.

FIGS. 19A-C depict a retraction process of the retractable member 614relative to the sheath member 612, when the retractable device 610 is inuse. When the tool head 650 moves from the exposed position as in FIG.19A toward a partially guarded position as in FIG. 19B and to theguarded position as in FIG. 19C, the retractable member 614 rotatesrelative to the sheath member 612.

When the retractable member 614 retracts from the exposed position inFIG. 19A to the partially guarded position in FIG. 19B, the sliding pin609 of the sheath member 612 enters the guiding groove 607 of theretractable member 614 from a rear end and slides along the guidinggroove 607. In one example, the sliding pin 609 slides along anengagement side 608 of the guiding groove 607. This drives theretractable member 614 to start to rotate. In the meantime, a rearportion of the bottom ramp 606 is forced against the lower end 692 ofthe compression member 680, thereby helping prompt the rotation of theretractable member 614.

When the retractable member 614 moves toward the guarded position asshown in FIG. 19C, the sliding pin 609 keeps sliding along the guidinggroove 607 and in turn keeps driving the retractable member 614 torotate. In such circumstances, the axial movement of the retractablemember 614 is translated to rotation of the retractable member 614. Onceit reaches the guarded position, the retractable member 614 is locked inplace.

As shown in FIG. 19C, in the guarded position, the sliding pin 609 hasslid to a front portion of the guiding groove 607 and in turn hasrotated the retractable member 614. In the meantime, the lower end 692of the compression member 680 slides along the bottom ramp 606 until thetops of both the latch member 616 and the compression member 680 arereceived in the top wall cutout 643 and the bottoms of the both thelatch member 616 and compression member 680 are received in the bottomwall cutout 691. As a result, the retractable member 614 is self-lockedat this guarded position. Even if a force is applied to push theretractable member 614 toward the exposed position, the bottom cutoutshoulder 605 will engage with the lower end 692 of the compressionmember 680 and prevent the retractable member 614 from moving forward.

When the user need to push the retractable member 614 to the exposedposition, the retractable member 614 needs to be rotated leftward tounlock the retractable device and then pushed to the exposed position.

The described embodiments are to be considered in all respects only asillustrative and not restrictive. The scope of the invention istherefore, indicated by the appended claims rather than by the foregoingdescription. All changes which come within the meaning and range ofequivalency of the claims are to be embraced within their scope.

What is claimed is:
 1. A self-locking retractable surgical knife,comprising: a sheath member having front and rear ends; a retractablemember including a support member and a blade supported by the supportmember, wherein the support member has a front end, a rear end and anelongated interior space; the retractable member being partiallydisposed in the sheath member and telescopically received in the sheathmember for movement between a guarded position wherein the blade isguarded in the sheath member, and an exposed position wherein the bladeextends out of the sheath member; top and bottom elongated andlongitudinally extended slots formed on the support member, wherein thetop slot is defined in a top wall of the support member and the bottomslot is defined in a bottom wall of the support member, a biasing memberdisposed in the interior space of the support member; a latch memberdisposed in the interior space of the support member, the latch memberhaving a release button projecting through the top slot of the supportmember and an opening defined in a top wall of the sheath member in thisorder, the latch member having a bottom section projecting through thebottom slot of the support member and abut an inner surface of a bottomwall of the sheath member; a compression member attached to the rear endof the sheath member at an attachment portion of the compression member,the compression member being tapered rearward from the rear end of thesheath member, the compression member being configured to bias thebiasing member toward the rear end of the support member, wherein therear end of the support member has a slot that allows the compressionmember to pass by; and a self-locking mechanism configured to translatean axial movement of the retractable member when the retractable memberis moving from the exposed position to the guarded position to rotation,thereby preventing the retractable member from moving forward relativeto the sheath member and self-locking the retractable member in theguarded position.
 2. The retractable surgical knife of claim 1, whereinthe locking mechanism comprises a top cutout and a bottom cutout definedin the top side and the bottom side of the support member, respectively;the top cutout and the bottom cutout extending in a same clockwise orcounterclockwise direction circumferentially from a side edge of the topslot and a side edge of the bottom slot, respectively, thereby allowingthe latch member to be received in the cutouts when the retractablemember is rotated relative to the sheath member.
 3. The retractablesurgical knife of claim 2, wherein at least one of the top cutout andthe bottom cutout includes a shoulder at a rear end of the respectivecutout, the shoulder being engageable with the attachment portion of thecompression member so as to lock and prevent the retractable member frommoving forward relative to the sheath member.
 4. The retractablesurgical knife of claim 2, wherein at least one of the top cutout andthe bottom cutout includes a ramp engageable with the attachment portionof the compression member or a rear end of the latch member so as tofacilitate the retractable member to start rotating relative to thesheath member, thereby guiding the latch member to be received in thecutouts.
 5. The retractable surgical knife of claim 4, the ramp iscurved generally toward an axial center of the top slot of the supportmember.
 6. The retractable surgical knife of claim 2, wherein thelocking mechanism comprises a sliding pin disposed on the inner surfaceof the bottom wall of the sheath member and a guiding groove; theguiding groove being configured to guide the sliding pin, when theretractable member retracts toward the guarded position, thereby drivingthe retractable member to rotate relative to the sheath member, andguiding the latch member to be received in the cutouts.
 7. A method ofassembling the retractable surgical knife of claim 1 comprising:inserting the rear end of the support member into the opening at the topwall of the sheath member, with the elongated top slot of the supportmember overlapping an elongated top slot of the sheath member;introducing the latch member into the interior space of the supportmember between a sliding pin of the sheath member and a rear end of theelongated top slot of the sheath member from the overlapped elongatedtop slots of the support member and the sheath member; and inserting thebiasing member into the interior space of the support member through abiasing member introduction slot of the support member.
 8. The method ofclaim 7, wherein before introducing the latch member into the interiorspace of the support member, the method further comprises: sliding theretractable member toward the rear end of the sheath member during whicha rear wall slot formed in a rear wall of the retractable member slidespast the compression member formed on the sheath member, and the topwall of the support member slides past a gap formed between thecompression member and the top wall of the sheath member; and lining upthe elongated top slot of the support member with the elongated top slotof the sheath member, when the rear end of the elongated top slot of thesupport member slides past a rear end of the elongated top slot of thesheath member.
 9. The method of claim 7, wherein before inserting thebiasing member into the interior space of the support member through thebiasing member introduction slot, the method further comprises: pushingforward the rear end of the support member; abutting a top surface ofthe release button to an inner surface of the top wall of the sheathmember and abutting a lower end of the latch member to an inner surfaceof the bottom wall of the sheath member; pulling the rear end of thesupport member rearward until a front end of the elongate top slot ofthe support member engages with a front surface of the release button ofthe latch member; pulling the retractable member further rearward;pushing the latch member to move rearward until the release button ofthe latch member snaps through a latch button slot of the sheath memberdue to a resilience force of the latch member; self-securing the releasebutton in the latch button slot of the sheath member, as a permanentlocation; and exposing the biasing member introduction slot at leastpartially exposed outside of the sheath member.
 10. A retractable toolholder, comprising: a sheath member having front and rear ends; aretractable member including a support member and a tool head retentionelement supported by the support member, wherein the support memberhaving an elongated interior space; the retractable member beingpartially disposed in the sheath member, and telescopically received inthe sheath member for movement between a guarded position wherein thetool head retention element is retracted into the sheath member, and anexposed position wherein the tool head retention element extends out ofthe sheath member; top and bottom elongated and longitudinally extendedslots formed on the support member wherein the top slot is disposedalong a top side of the support member and the bottom slot is disposedalong a bottom side of the support member, a top opening defined in atop side of the sheath member; a biasing member disposed in the interiorspace of the support member; a latch member for latching the retractablemember in the exposed position, the latch member having a release buttonbeing receivable in the top opening of the sheath member and the topslot of the support member, thereby locking the sheath member and thesupport member against further relative movement; a compression memberattached to the rear end of the sheath member at an attachment portionof the compression member, the compression member being tapered rearwardfrom the rear end of the sheath member, the compression member beingconfigured to bias the biasing member toward a rear end of the supportmember, wherein the rear end of the support member has a slot thatallows the compression member to pass by; and a self-locking mechanismconfigured to translate an axial movement of the retractable member whenthe retractable member is moving from the exposed position to theguarded position to rotation, thereby preventing the retractable memberfrom moving forward relative to the sheath member and self-locking theretractable member in the guarded position.
 11. The retractable toolholder of claim 10, wherein the locking mechanism comprises a top cutoutand a bottom cutout defined in the top side and the bottom side of thesupport member, respectively; the top cutout and the bottom cutoutextending in a same clockwise or counterclockwise directioncircumferentially from a side edge of the top slot and a side edge ofthe bottom slot, respectively, thereby allowing the latch member to bereceived in the cutouts when the retractable member is rotated relativeto the sheath member.
 12. The retractable tool holder of claim 11,wherein at least one of the top cutout and the bottom cutout includes ashoulder at a rear end of the respective cutout, the shoulder beingengageable with the attachment portion of the compression member so asto lock and prevent the retractable member from moving forward relativeto the sheath member.
 13. The retractable tool holder of claim 11,wherein at least one of the top cutout and the bottom cutout includes aramp engageable with the attachment portion of the compression member ora rear end of the latch member so as to facilitate the retractablemember to start rotating relative to the sheath member, thereby guidingthe latch member to be received in the cutouts.
 14. The retractable toolholder of claim 10, the ramp is curved generally toward an axial centerof the top slot of the support member.
 15. The retractable tool holderof claim 11, wherein the locking mechanism comprises a sliding pindisposed on an inner surface of a bottom wall of the sheath member and aguiding groove; the guiding groove being configured to guide the slidingpin, when the retractable member retracts toward the guarded position,thereby driving the retractable member to rotate relative to the sheathmember, and guiding the latch member to be received in the cutouts.